Bubbling algae to timber cubes: IBA eco buildings in Hamburg - video

Oliver Wainwright visits the International Building Exhibition (IBA), a six-year experiment to build a zero-carbon extension to Hamburg in northern Germany. The project is home to all kinds of Passivhaus buildings, solid timber construction, the recycling of greywater, and even a building with a bubbling bio-reactive algae facade. Wainwright meets some of the key representatives of the project to examine a variety of different examples of eco architecture